Grain-drier



2 Sheets-Sheet 1.

(No Model.)

J. s.. METCALP.

GRAIN DRIER.

4Patented Apr. 2l, 1,896.

l my

l 2 Sheets-Sheet 2.

' (No Model.)

' J. S. METCALF.

GRAIN DRIRE. No. 558,508.

Patented Apr. 21, 1896.

ANDREW asmmlM UNITED STATES PATENT OFFICE.

JOHN S. METCALF, OF CHICAGO, ILLINOIS.

GRAIN-DRIER.

SPECIFICATION forming part 0f Letters Patent No. 558,508, dated April21, 1896.

Application led March 28, 1895. Serial No. 543,466. (No model.) i

To @ZZ whom, t may concern:

Be it known that I, JQHN S. METCALF, a citi- Zen of the United States,residing at Chicago, in the county of Cook and State of Illinois, haveinvented certain new and useful Improvements in Apparatus for DryingGrain, of which the following is a specification, reference being had tothe accompanying drawings, which are made a part hereof, and in which-Figure l is a perspective view of an apparatus embodying the invention,some of the parts being broken away. Fig. 2 is a section thereof takenin irregular vertical planes. Fig. 8 is a vertical section thereof onthe line 3 3, Fig. 2. Fig. 4 is a horizontal section thereof under aslight modification, the section being taken in two planes.

The ratio or quantity of aqueous vapor that can be absorbed by air, or,in other words, its degree of saturation, depends upon the ternperature,being greater as the temperature increases, and vice versa. Consequentlyif ya body of atmospheric air be heated toa given temperature and bethen passed through a body of wet grain or any other material of a verymuch lower temperature, during its entire passage through the grain thetemperature of the air will decrease. It follows, therefore, that afterit has become saturated to its fullest capacity from that time on, solong as its temperature continues to fall, the vapor will be condensedand will settle upon the grain or whatever else it comes-in contactwith. Hence if a current of dryheated air be passed through a body ofgrain which is uniformly damp there will come a time when the grain willbe perfectly dry in the vicinity of the point where the air enters itand damp from that vicinity to the point where the air leaves it, andthe degree of this dampness will increase in the direction traveled bytheair, being greatest where the air leaves the grain.

The object of the present invention is to provide an apparatus fordrying grain of such construction that the objection above pointed outwill be obviated as much as possible; and to this end the inventionconsists in the features that are particularly pointed out in the claimshereinafter.

In the drawings, A represents a casing which may be of any suitableconstruction,

and B and C represent two partitions arranged within the casing anddividing its interior into three compartments or chambers D, E, and F.lVith the chamber D communicates a pipe G, which leads from thedischarge-nozzle of a fan H, the eye of which is in communication withan air-heater I, which is not shown in detail, because the presentinvention is not limited to a heater of any particular construction. Anyheater that will raise the temperature of the air to the desired degreewill answer the purpose and be included within the term heater as usedin this specification.

The grain is dried in the chamber E, which in the example shown in thedrawings is traversed by a number of ducts or passages J and K. In theexample shown each of these passages is constructed of a heavy centralbeam or timber 7c, to the opposite sides of which are secured boardsle', that project downward some distance below it, these three partstogether forming a sort of inverted trough; but I desire to have itunderstood that in its broadest aspect the present invention is notlimited to an air-passage of any particular construction. In the exampleshown these passages are arranged quincuncially or staggered, and whilethis arrangement is preferred, still it is not essential.

The passages J constitute what may properly be termed theinlet-passages, and each of them is in open communication with thehot-air chamber D through an opening L of ample capacity formed throughthe partition B.

The passages K may properly be termed the outlet-passages, and each ofthem is in open communication with the chamber F through an opening K ofample capacity formed through the partition C. The inletpassages beingclosed, excepting as above described, it follows that hot air forcedinto them from the hot-air chamber D will escape from their open lowersides, and as each of them occupies a position that is central with.relation to each group of four outlet-passages the hot air will seekthese four outlet-passages, and thus permeate the mass of grain in alldirections. It will be understood, of course, that while all of thesepassages are buried under the grain, none of them are filled, as

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the grain is not sufficiently mobile to flow upward between theirdepending sides.

Grain-driers having passages constructed and arranged substantially inthe manner described have long been in use, and in using them it isfound that, owing to the facts stated in the early part of thisspecification, the grain in the immediate vicinity of the open bottom ofthe inlet-passages soon becomes thoroughly dried, and that from thispoint to the point where the air leaves the grain and enters theoutlet-passages the dampness increases, the grain immediatelybeneathsaid outlet-passages being thoroughly soaked.

It is found also that the soaking of the grain at this point is dueprincipally to the fact that much of the moisture absorbed by the air asit passes through the grain is condensed and precipitated after enteringthe outlet-passage. This being so, it follows that if the temperature ofthe air can be maintained at a sufficient degree after it enters theseoutlet-passages t-here will be no condensation and precipitation withinthem, and the evil resulting therefrom will therefore be avoided. Tothis end I introduce into each of these outlet-passages a volume of dryair atasufiiciently high temperature to raise and maintain thetemperature of thc air, leaving the grain above the dew-point. This,then, is my improved method of drying grain. Broadly stated, it consistsin passing heated air through the body of grain and introducing to thisair, as it leaves the grain saturated with vapor, a sufficient quantityof dry heated air to prevent condensation and consequent precipitation,and I desire to have it understood that in its broadest aspect myinvention is not limited to an apparatus of anyparticular constructionfor carrying out this improved method, albeit I prefer the apparatusshown in Figs. l, 2, and 3 of the drawings, as it is simple, cheap, andeffective.

In this apparatus the dry heated air is introduced into theoutlet-passages from the hot-air chamber D, through -perforations N,formed through the partition B, opposite the ends of said ducts orpassages, the relative capacities of the openings L and N being suchthat the air passing through L will have suiiicient pressure to permeatethe grain in the manner described.

As shown in Fig. 4, the dry air that is introduced into theoutlet-passages is not taken from the air-chamber D, but from a separatechamber O,f rom whichit is conducted through the chamber D and to theoutlet-passages by tubes I. This chamber O may be supplied with air fromthe fan II through a branch pipe Q, and the force of the air enteringthe chambers D and O may be regulated by valves R and S, located in thepipes G and Q, respectively, or the fan II may be used exclusively forsupplying the chamber D, and a separate fan T (indicated by dottedlilies) provided for supplying the chamber O; but these are mere detailsin construction which will depend upon the circumstances in individualcases, and the invention is not to be understood as being limited tothem.

The term passage, as used in this speciiieation in referring to theoutlet-passages K, is not to be interpreted as being limited to apassage of any particular size, shape, or construction; but it is to beconstrued broadly and includes any duct, passage, space, or chamber ofwhatever shape, size, or construction into which the air enters after itleaves the material being dried.

lVhat I claim as new, and desire to secure by Letters Patent, is-

l. In a drying apparatus, the combination with a chamber in which thematerial to be dried is placed, of means for introducing heated air intosaid chamber, an outlet-passage into which the air enters after leavingthe material being dried, means for introducing heated air into saidoutlet-passage, and an outlet-opening through which the mixed volumes ofair escape from said passage without again entering the drying-chamber,substantially as set forth.

2. In a drying apparatus the combination with a chamber in which thematerial to be dried is placed, of means forintroducing heated air intosaid chamber, a number of outletpassages into which the air enters afterleaving the material being dried, and means for introducing heated airinto each of said outlet-passages, substantially as set forth.

3. In a drying apparatus, the combination with a chamber in which thematerial to be dried is placed, of means for introducing heated air intosaid chamber, an outlet-passage traversing said chamber, saidoutlet-passage being open at bottom for receiving the air after itleaves the material being dried, and means for introducing heated airinto said outlet-passage, substantially as set forth.

4. In a drying apparatus the combination with a chamber in which thematerial to be dried is placed, of means for introducing heated air intosaid chamber, a number of outletpassages open at bottom for receivingthe air after it leaves the material being dried, a chamber with whichall of said outlet-passages communicate at their discharge ends, andmeans for introducing heated air into the opposite end of each of saidpassages, substantially as set forth.

5. In a drying apparatus the combination with a chamber in which thematerial to be dried is placed, of a number of air inlet and outletpassages traversing said chamber, a chamber with which all of saidpassages communicate at one end, means for forcing heated air into saidchamber, and a chamber with which all of the outlet-passages communicateat the other end, the passages being open at the under side,substantially as set forth.

JOIIN S. METCALF.

XVitliesses L. M. I-IOPKINs, S. E. SHARON.

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